211221247 has 2 divisors, whose sum is σ = 211221248. Its totient is φ = 211221246.

The previous prime is 211221229. The next prime is 211221301. The reversal of 211221247 is 742122112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 211221247 - 2¹⁵ = 211188479 is a prime.

It is a super-2 number, since 2×211221247² = 89228830368470018, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211221847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105610623 + 105610624.

It is an arithmetic number, because the mean of its divisors is an integer number (105610624).

Almost surely, 2^211221247 is an apocalyptic number.

211221247 is a deficient number, since it is larger than the sum of its proper divisors (1).

211221247 is an equidigital number, since it uses as much as digits as its factorization.

211221247 is an evil number, because the sum of its binary digits is even.

The product of its digits is 448, while the sum is 22.

The square root of 211221247 is about 14533.4526868188. The cubic root of 211221247 is about 595.5421906202.

Adding to 211221247 its reverse (742122112), we get a palindrome (953343359).

The spelling of 211221247 in words is "two hundred eleven million, two hundred twenty-one thousand, two hundred forty-seven".